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JavaScript: Replace the first digit in a string (should contains at least digit) with $ character

JavaScript Basic: Exercise-136 with Solution

Write a JavaScript program to replace the first digit in a string (should contains at least digit) with $ character.

Pictorial Presentation:

JavaScript: Replace the first digit in a string (should contains at least digit) with $ character.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Replace the first digit in a string (should contains at least digit) with $ character</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function replace_first_digit(input_str) {

  return input_str.replace(/[0-9]/, '$');
}
console.log(replace_first_digit("abc1dabc"));
console.log(replace_first_digit("p3ython"));
console.log(replace_first_digit("ab1cabc"));   

Sample Output:

abc$dabc
p$ython
ab$cabc

Flowchart:

Flowchart: JavaScript - Replace the first digit in a string (should contains at least digit) with $ character

ES6 Version:

function replace_first_digit(input_str) {

  return input_str.replace(/[0-9]/, '$');
}
console.log(replace_first_digit("abc1dabc"));
console.log(replace_first_digit("p3ython"));
console.log(replace_first_digit("ab1cabc"));

Live Demo:

See the Pen javascript-basic-exercise-136 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to test if a given integer is greater than 15 return the given number, otherwise return 15.

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JavaScript: Tips of the Day

Classes/function constructors

class Person {
  constructor() {
    this.name = 'Owen';
  }
}

Person = class AnotherPerson {
  constructor() {
    this.name = 'Eddie';
  }
};

const member = new Person();
console.log(member.name);

We can set classes equal to other classes/function constructors. In this case, we set Person equal to AnotherPerson. The name on this constructor is Eddie, so the name property on the new Person instance member is "Eddie".

Ref: https://bit.ly/3jFRBje